[php mysql insert multiple row data problem]

i have a big problem this script seems working properly but data base looks so badly. just like his
-------------------------
|word |initial |logic|
-------------------------
|ansion | 1 | a |
|ncel | 1 | a |
|tree | 1 | a |
| bandege | 1 | a |
-------------------------
but i want words mansion, cancel, bigtree, bandage. every time no problem how many rows here last row working exactly what i want. please help me. am using wamp php 5.4 mysql 5.5 and apache 2.22.22.


//php script
<?php
$words= array('mansion','cancel','bigtree','bandege');

foreach( $words as $key => $word ){
$initial = "1";
$logic = "a";
$obj = new en_word( array(
"word"=> isset( $word ) ? (string) $word :"",
"initial"=> isset( $initial ) ? (string) $initial :"",
"logic"=> isset( $logic ) ? (string) $logic :""
) );
$obj->insert();
}
?>

//en_word class
<?php
class en_word extends DataObject {
protected $data = array(
"word" => "",
"initial" => "",
"logic" => ""
);
public function insert() {
$conn = parent::connect();
$sql = "INSERT INTO " . TBL_EN_WORD . " (
word,
initial,
logic
) VALUES (
:word,
:initial,
:logic
)";
try {
$st = $conn-> prepare( $sql );
$st-> bindValue( ":word", $this->data["word"], PDO::PARAM_STR );
$st-> bindValue( ":initial", $this->data["initial"], PDO::PARAM_STR );
$st-> bindValue( ":logic", $this->data["logic"], PDO::PARAM_STR );
$st-> execute();
parent::disconnect( $conn );
} catch ( PDOException $e ) {
parent::disconnect( $conn );
die( "Query failed: " . $e-> getMessage() );
}
}
}
?>

//dataobject class
<?php
abstract class DataObject {
protected $data = array();

public function __construct( $data ) {
foreach ( $data as $key => $value ) {
if ( array_key_exists( $key, $this-> data ) ) $this-> data[$key] = $value;
}
}

protected static function connect() {
try {
$conn = new PDO( DB_DSN, DB_USERNAME, DB_PASSWORD );
$conn-> setAttribute( PDO::ATTR_PERSISTENT, true );
$conn-> setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
} catch ( PDOException $e ) {
die( "Connection failed: " . $e-> getMessage() );
}
return $conn;
}

protected static function disconnect( $conn ) {
$conn = "";
}
} ?>

//mysql en_word table structure
word VARCHAR(50) NOT NULL UNIQUE,
initial VARCHAR(25) NOT NULL,
logic TEXT NOT NULL